The present invention relates to a procedure for preparing a food additive as defined in the preamble of claim 1. Moreover, the invention relates to a food additive, its use and a preparation containing the additive.
A balance of intestinal microbes is a condition for the health and well-being of animals and for their productivity. Disturbances of this balance appear as diarrhoea and other intestinal health problems and may even lead to death.
The commonest nutritional method used to avoid the effects of noxious microbes on the health of single-stomach animals is to add various antibiotic and chemotherapeutic substances inhibiting microbial growth to the fodder used to feed the animal. To maintain intestinal balance and to avoid the use of antibiotics, it is also possible to use fodders containing added probiotic products, such as various microbes, acids and yeasts.
Another method used to prevent intestinal diseases is to inhibit the adherence of noxious microbes on the wall of the intestine. A method used to achieve this is to add to the fodder mixtures various oligosaccharides, which adhere to the receptors on the intestinal wall or to microbial receptors, thus preventing noxious microbes from settling on the intestinal wall. Moreover, it has been established that certain oligosaccharides, e.g. fructo-oligosaccharides promote the growth of bifidomicrobes beneficial to animals.
A problem with the use of antibiotics is that it promotes the development of microbial strains immune to antibiotics and thus leads to health risks to humans. A problem with probiotic products is that they have a variable and generally low efficacy and are quite expensive to use. Likewise, a problem with fodders containing pure oligosaccharides is that they have a variable and generally low efficacy in preventing intestinal diseases. In addition, the price of pure oligosaccharides is high.
The object of the present invention is to eliminate the problems described above.
A specific object of the present invention is to disclose a procedure for preparing a food additive having a more efficient effect on intestinal microbes that promotes the health and/or growth of animals.
A further object of the invention is to disclose a food additive that makes it possible to reduce more effectively intestinal diseases in animals.
A further object of the invention is to disclose the use of a new additive prepared according to the present invention and a preparation containing such an additive.
As for the features characteristic of the invention, reference is made to the claims.
In the procedure of the invention for preparing a food additive, a filtered brewing yeast raw material containing oligosaccharides and/or polysaccharides is treated so that its cell structure is changed and the amount of free oligosaccharides and/or polysaccharides and/or the amount of oligosaccharides and/or polysaccharides on the surface of the cell structures are/is increased, i.e. e.g. the cell structure breaks up, to release the oligosaccharides and/or polysaccharides for use to prevent intestinal diseases. This treatment can also be used to release said components.
The invention also discloses products prepared by the method of the invention, their use and preparations containing additives according to the claims.
In a brewing yeast raw material containing oligosaccharides and/or polysaccharides, the oligosaccharides and/or polysaccharides are fixedly bound to the cell walls and other insoluble structures in the raw material. Investigations carried out in conjunction with the present invention revealed that adding such raw material directly to fodder does not produce any favourable effects of oligosaccharides; the animal (and human) digestive system is generally unable to decompose e.g. the cell wall of a yeast cell and release the desired oligosaccharides and/or polysaccharides. It was further established in the investigations that by treating the raw materials so that the amount of free oligosaccharides and/or polysaccharides and/or the amount of oligosaccharides and/or polysaccharides on the surface of the cell structures are/is increased, e.g. the cell structure of the raw material breaks up, a product is obtained that, when given to an animal together with fodder, substantially reduces intestinal diseases in the animal.
The mechanism of action of the product obtained in preventing intestinal diseases has not been fully elucidated in the investigations carried out, so it is based on various assumptions. According to one model, using the products obtained by the present method in conjunction with fodders inhibits microbial adherence to the intestine, in other words, the oligosaccharides and/or polysaccharides and/or other substances released in conjunction with the break-up of the cell structure of the raw material are assumed to act as analogues to the receptors of noxious microbes, such as E.coli, in the intestine and to inhibit the ability of the microbes to attach to the wall of the intestine.
According to another model, the products obtained via break-up of the raw material cell structure affect the growth of noxious microbes in both the small and the large intestines, in other words, beneficial intestinal microbes, such as lactic acid bacteria and bifidobacteria, are able to utilise the oligosaccharides and/or polysaccharides for their nutrition whereas noxious microbes, such as E.coli and salmonella, are not. This favours the growth of beneficial microbes at the expense of noxious ones.
According to a third model, the decomposition products obtained via hydrolytic treatment of the raw material are assumed to have an effect on the immune reaction of the animal, i.e. certain raw material components, e.g. saccharine structures containing phosphor in yeast may improve the animal""s immune reaction, thereby inhibiting intestinal diseases. Further the hydrolytic treatment of filtered yeast effects on the type and the strength of immune response.
Further, the components formed via hydrolytic treatment of the raw material may affect the adsorption of toxins; i.e. the components may bind and neutralise microbial toxins, thus inhibiting intestinal diseases. The assumed mechanisms of action described above may also work in combination, inhibiting intestinal diseases in animals.
Brewing yeast is produced as a side product of brewery industry. Normally, a brewing yeast mixture is transferred after the brewing to storage tanks in which the brewing yeast becomes precipitated on the tank base. After this, the beer remaining on the surface is separated. The dry matter of a brewing yeast produced in this way usually varies between 7-13% by weight.
In the method in accordance with the invention, the brewing yeast that became precipitated on the bottom of the tank is filtered mechanically and/or pneumatically. The brewing yeast may be filtered by any known filtering method. To prevent the filters, e.g. filtering discs, from getting blocked up, a vibrator such as a micro vibrator may be used at a high frequency and/or some other corresponding technique which prevents the filter from getting blocked up. The density of the filter is chosen based on the particle size.
The dry matter of a brewing yeast filtered in accordance with the invention is 15% by weight at the minimum, preferably 18-20% by weight.
In the filtered brewing yeast raw material used, the oligosaccharides and/or polysaccharides are bound to the cell structures of the raw material. Oligo- and polysaccharides can be released from the raw material by breaking up the cell structure of the raw material hydrolytically using an acid and/or an alkali, and/or enzymatically. Acids usable in the hydrolysis are e.g. ordinary mineral acids, such as hydrochloric acid, sulphuric acid, phosphoric acid, nitric acid, etc., as well as strong organic acids, such as formic acid, acetic acid, propionic acid, etc. The pH range used in acid hydrolysis may be below 4, e.g. about 2. In alkali hydrolysis, the alkalis used may be e.g. ordinary alkaline hydroxides such as sodium hydroxide, caustic potash etc., ammonium hydroxide or other alkalis releasing oligosaccharides and/or polysaccharides.
Among the enzymes usable in enzymatic hydrolysis are various cellulolytic and proteolytic enzymes, e.g. cellulases, acid or alkaline proteases, which may be selected according to the properties of the raw material to be used. In hydrolysis of yeast, e.g. Torula yeast, the culture solution of a derivative of Trametes sanguinea can be used. Furthermore, other added enzymes, proteases, ribonucleases and deaminases can be used in the hydrolysis. The enzyme treatment can also be implemented using a combination of several enzymes, simultaneously or in succession; e.g. protease treatment or protease treatment followed by ribonuclease treatment and deaminase treatment, in which process the protease breaks down the RNA, and when the amino acids are released, the ribonuclease breaks down the RNA into various nucleotides and the deaminase converts the adenosine mononucleotide into inosine mononucleotide. The protease treatment can be implemented using any known protease. Generally, the procedure can be implemented using enzymes mentioned in the specifications referred to below and/or other known enzymes having the desired effect of breaking up the cell structure, together and/or separately, e.g. as described in the specifications referred to below.
In a hydrolysis, the yeast can be heated to a temperature of over 40xc2x0 C., in autolysis and enzymatic hydrolysis e.g. to 40-65xc2x0 C. and in acid and alkalic hydrolysis e.g. 70-90xc2x0 C.. The duration of the heating may vary depending on the temperature, e.g. between 1-12 hours.
Both the soluble and the insoluble fraction obtained via filtration and hydrolysis contain certain amounts of the desired oligosaccharides and/or polysaccharides. The soluble and insoluble fraction can expressly be used e.g. in the production of a feed stuff or foodstuff; on the other hand, the soluble fraction or the insoluble fraction can be used.
Hydrolytic decomposition of yeasts is described in the following patent specifications and applications: U.S. Pat. Nos. 3,914,450, 3,443,969, 5,288,509, EP 299 078, JP 57-219695 and PCT/FI/96/00326. These and other prior-art methods can be used in conjunction with the present invention, the usable fraction being expressly the fraction containing oligosaccharides and/or polysaccharides or the non-fractionated product obtained as such. Thus, specification PCT/FI96/00326 describes the recovery of flavours, such as nucleotides, peptides and amino acids e.g. from brewing yeast and baking yeast, whereas in the present invention it is primarily the other components that are recovered, and, if desired, the flavours can be separated e.g. as described in the specification referred to. On the other hand, the separation of flavours can be omitted; in other words, part or all of the flavours can be included in the product prepared according to the invention.
Besides hydrolytic treatment of filtered brewing yeast, it is also possible to apply a treatment of the raw material with a detergent and/or a treatment that breaks up the cell structure of the raw material, e.g. by subjecting the cell structure to a mechanical, hydrostatic and/or pneumatic force, and/or to a heat treatment. Moreover, it is possible to use combinations of the above-mentioned methods, e.g. a treatment breaking up the cell and/or a heat treatment combined with an enzymatic or other hydrolytic treatment. If desired, the product obtained via hydrolytic treatment and/or via a treatment breaking up the cell and/or via heat treatment can be treated with a detergent to wash it.
If desired, the food additive produced according to the invention can be processed further, e.g. by fractionating or concentrating the saccharine structures obtained in the treatment. The further treatment, such as fractionation or concentration, can be implemented by any method known in itself. The fractionated and/or concentrated products obtained can be used as such for fodder or food, or they can be mixed with feed stuffs and/or foodstuffs known in themselves.
The product prepared by the method of the invention can be added to a fodder or foodstuff as such, moisturised or dried, and it can generally be treated as desired.
The food additive prepared by the method of the invention can be used in fodders for single-stomach animals, e.g. pigs, poultry, calves, fur animals such as foxes and minks, pets such as dogs and cats, horses, especially foals, fish and so on, to prevent intestinal diseases. The food additive can be used in fodders/foods for single-stomach animals in amounts of approx. 0.05-1.5 w-%, preferably about 0.1-1 w-% of the total amount of fodder, calculated in terms of dry matter and depending on the degree of hydrolysation; the percentages have been calculated based on a degree of hydrolysation of 50%; the percentages depend on the degree of hydrolysation. The additive can be used together with fodder/food or as such. The additive is preferably so used that the amount of additive used is 0.1-0.6 g/kg, calculated from the daily ration of foodstuff and/or feed stuff in terms of dry matter per kilogram of the animal""s living weight.
The food additive of the invention can also be used in food for people, e.g. in food products for children or adults or as a preparation served separately to promote health, to balance intestinal microbes and to inhibit intestinal diseases.
The feed additive prepared by the method of the invention, when added to fodder intended for animals, effectively inhibits the growth of harmful micro-organisms and promotes the growth of beneficial microbes. At the same time, the growth of the animals, utilisation of fodder and the overall economy of production are improved. The feed additive according to the invention is approximately 30% more efficient in preventing the attachment and the growth of noxious microbes than a product prepared from an unfiltered brewing yeast. The invention improves the economy of the production of the feed additive and the preparation according to the invention. Further, the environmental emissions caused by the production are reduced because the animal is able to utilise the fodder more effectively. In addition, the use of the products of the invention, i.e. organic feed products, in the fodder for animals makes it possible to stop using antibiotics in fodder. The risk for the development of microbial strains immune to antibiotics is reduced and the health risks they cause for humans are also reduced.
In the following, the invention will be described in detail by the aid of embodiment examples.